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Strange problem

Discussion in 'GM Powertrain' started by sierra11, Dec 27, 2012.

  1. sierra11

    sierra11 Rockstar 100 Posts

    Hey guys so I have been having this issue for awhile now but I thought I would be able to fix it by replacing the 4 wheel drive switch. My truck has been throwing itself into 4 wheel drive randomly. I'll be driving down the road and I'll look over and the 4 low/high will be lit but not on the dash? And sometimes when this happens I also lose almost all engine power and I can barley get up any speed until I pull over and put it back into 2 wheel. What is going on with the truck? It happens randomly but sometimes at the worst time.

    Oh and this problem isn't throwing a trouble code.
    Last edited: Dec 27, 2012
  2. RayVoy

    RayVoy Well-Known Member 2 Years 1000 Posts

    I could very well be the selector switch. I can't tell from your description if you have changed it.

    If you changed it and you still have the problem, you probably need a new TCCM (transfer case control module)
  3. sierra11

    sierra11 Rockstar 100 Posts

    What I changed was the 4 wheel drive switch which is the module that houses the 4 hi 4 low, etc. A new TCCM? I'll look into that and see. What I don't understand is how is this not throwing any kind of code?
  4. RayVoy

    RayVoy Well-Known Member 2 Years 1000 Posts

    Does the "service 4 wheel drive" light ever come on?

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